I of course have made no secret I hate the Klingon design. Partly because it's so far different from their previous design
"Design," singular? Come on. The DSC version is roughly the
eighth distinct Klingon design, after Kor/Kang style, Kras/Koloth style, TMP style, TSFS style, TVH-TUC style, Michael Westmore style, and Kelvin style.
I'll admit, Disco's insistence on being Prime makes no real sense to me.
There are many things in Prime that make little sense. There are many contradictions between different versions of Trek and within any single version of Trek, and fans have spent decades arguing over them and trying to reconcile them. People always talk as if the newest version of Trek is some unprecedented departure from a previously homogeneous mass, but they're forgetting how many previous differences and discontinuities they've had to blur together in their minds to create that perception of a homogeneous mass. Remember that
every new version of Trek going back to the '70s has been rejected by some fans as too radical a change from what came before. But the only difference between the newest version and all the earlier versions, as a rule, is that fandom has had more time to make up excuses and handwaves to fit the older versions together despite their contradictions.
Having it set a decade before TOS we know right away that the Klingon War won't amount to much, since both the Federation and the Klingons were a mutual threat to each other during TOS.
Aside from the magnitude and scope of the war as portrayed, I think it actually helps clarify some things in TOS. It provides a reason why the
Enterprise crew are so hostile toward the Klingons, why there seems to be a grudge there more intense than their attitude toward the Romulans, say. It fits with the mention of a Klingon attack on a Federation colony years before "Day of the Dove"; Chekov imagined losing a brother in that raid, but the other characters reacted as if the raid itself were a real, known event. And so on. I do wish it had been briefer and not so sweeping in scope; that would've fit better. But it's very, very far from being the first thing in Trek continuity that's an awkward fit.
And the spore drive will obviously be abandoned to allow for why we never hear of it again in the other shows.
Again, that is not even remotely close to the first time that's happened. Trek is littered with forgotten technological revolutions and breakthrough discoveries that realistically should have been revised, retried, and perfected, but instead were abandoned without explanation. Sargon's android technology. Kironide telekinesis. Fabrini medicine. The Genesis Device. The soliton wave. DS9's first season alone introduced quick-cloning, consciousness transfer upon death, and nanites that could cure any disease or injury, which collectively should've brought immortality. And then there are the simpler things that are abandoned, like the seat restraints and security armor of the TOS movie era, which are gone by TNG. Or the uniforms with built-in heating elements in "Spock's Brain," which are completely forgotten by the movie era. Or the dozen redundant safeguards against warp-core breaches in TNG: "Contagion" that Starfleet seemed to stop using in later seasons, when warp cores breached if you looked at them funny.